The present invention relates generally to a golf club head, and more particularly to a golf club head comprising a head case and a ball-striking plate which is doubly fused with the head case.
As shown in FIG. 1, a prior art wooden golf club head 80 is formed of a head case 81 and a ball-striking plate 82 which is joined with the head case 81 by welding such that the plate 82 is first joined with the front side of the case 81, and that the annular line between the case 81 and the plate 82 is fused by the welding material to form an annular welded portion 83 fusing the plate 82 with the case 81.
As shown in FIG. 2, another prior art wooden golf club head 85 is formed of a case 86 and a ball-striking plate 87. The case 86 has an arcuate front edge. The plate 87 has a back whose outer peripheral portion and the case 86 form an annular groove 88. The welding is done along the groove 88 to form a welded portion 89 of a relatively greater area and a relatively greater fusion strength.
The U.S. Pat. No. 5,871,408 issued to this inventor of the present invention discloses a wooden golf club head 90 comprising a club head case 91 and a ball-striking plate 92 fused in the recess 93 of the case 91, as shown in FIG. 3. The fusion portion (the wall and the bottom of the recess 93) of the case 91 and the plate 92 is provided with a welded layer 94 which is formed by a molten welding material.
Such prior art golf club heads as described above are defective in design in that the strength of their respective fusion portion is inadequate, and that their fusion portion are apt to crack upon impact of the ball.
The primary objective of the present invention is to provide a golf club head free from the structural deficiency of the prior art golf club heads described above.
In keeping with the principle of the present invention, the foregoing objective of the present invention is attained by a golf club head comprising a head case of a metal, and a ball-striking plate of a metal. The head case has a recess extending from the front side of the case toward the rear side of the case. The ball-striking plate is joined with the head case such that the peripheral edge of the ball-striking plate is fused with the edge opening of the recess, and that the ball-striking plate is joined with the head case by a soldered layer formed by the molten hard solder, and that an annular fusion portion is formed along the line between the head case and the ball-striking plate.